This Wordpress plugin providing a shortcode for accepting donations through PayPal. The button can optionally show the number of donations made in a bubble.
Example shortcode:
[paypal-donate id="my-widget"]
The shortcode will insert a small button that links to the PayPal donation page. The button is loaded through an iframe to avoid clashes with existing style sheets. This iframe can also be embedded in external web sites that do not use Wordpress. Further info can be shown to the right of the button in a bubble.
Go to the PayPal Shortcode settings page to set up widgets. Follow the instructions to find you PayPal business ID and choose an identifier for the widget that will be used in the shortcode. Name and currency can be chosen as desired (although PayPal will limit the possible currencies) and the name will appear on the donation page.
It is also possible to use shortcodes in Wordpress widgets (e.g. in the side bar) but this requires an additional plugin to be installed (e.g http://wordpress.org/extend/plugins/shortcodes-in-sidebar-widgets/).
Here is a demo of the plugin: http://jonls.dk/ . The button appears in the sidebar.
Copy the directory paypal-donate into /wp-content/plugins.